[Scpg] [Lapg] Interesting perspective about invasive species
Adam Green
Green at sbcc.edu
Thu Apr 17 15:30:02 PDT 2008
Just another thought to consider. Often it is said that X supports greater biodiversity than Y. One thing that is not looked at is what actual species make up that biodiversity. If there are 35 species in a particular habitat in California that are only found in California, and that habitat is changed by introducing species from outside, and the biodiversity changes as a result to say 40 species, then the conclusion would be that biodiversity has increased and that is thought of as good. What if, however, the make up of those 40 species are 35 from Europe and only 5 from the original California group (loss of 30 California species)? Then, what we have done is homogenized biodiversity. If the same 35 species from Europe come to dominate North America, then the number looks high, but it is a net loss of global biodiversity because it is the same set of species as what appears in Europe. If a disease or climatic change impacts that group, then both Europe AND N. America are affected.
It is true that species have moved around the planet for millions of years, but the rate at which it is happening now is unprecedented and the resulting "non-native" biological communities may not be well adapted to the longer term changes in a "native" system making us more susceptible to rapid collapse. Preserving native biodiveristy means preserving gene pools that contain traits that may make a population resistant to longer term droughts, more frequent fires, or some other environmental challenge that has occurred sometime in the evolutionary history of that local population and has led to natural selection of those traits. The non-natives may do fine for a while, but if they take over and eliminate the natives during a time when these non-natives can prosper (ample rain, disturbance, etc.), then we may be left with significant declines in diversity when the system changes (i.e. goes into a hundred year drought).
We also have to consider ecosystem functions that we may not even understand. The native biological community may provide some function that when lost makes life for humans more challenging. Some are obvious, but others may be more subtle. These are very complex systems that have been evolving for a lot longer than we have been conscious of them.
My hope is that when we practice permaculture and manipulate a system we do so with a deep sense of responsibility. Anything you place in your design is your responsibility for as long as it is there. Start with natives, then proven exotics, and if you must use unproven exotics, then keep them close and observe them carefully so that you can remove them if they show signs of destructive spread. Always remember that we are seeking to regenerate function, don't introduce something that can turn around and decrease function once it leaves your land.
Be careful about claims that an invasive creates benefits. The zebra mussel also concentrates contaminants increasing the biomagnification of toxins by several hundred times- ends up in fish that we eat.
Finally, we have a great deal to gain by learning from other areas of study. Ecology is also based on Protracted and Thoughtful Observation. Much of the data on invasive species is collected by people who are just as concerned about the overall continuation of the human species and functioning ecosystems as those in permaculture. To call researchers in this field "racists" or "plantists" will not create a collaborative community. Words like these create immediate barriers that take a very long time to dismantle. Every effort to eliminate "invasives" is designed to remove something we determined we didn't want. We must also remember that permaculture is designed to create something we decided we do want. Both are based in human values. If you go in and sheet mulch a lawn and plant food, are you a "plantist" because you clearly hate lawn? If you rehabilitate soil and create a prairie are you "racist" against open ground? No, you made a choice based in human value and a desire to do something good for you and the ecosystem that supports you. I feel there are great benefits to finding common ground and building from there. To disregard years of observation and data collection by well trained ecologists is not unlike disregarding years of observation by an indigenous farmer. Understand the biases, be open to possibilities, and proceed with humility. Permaculture can benefit from a realtionship with the scientific community and Ecology is one of the closest forms in the biological sciences.
With respect and hope, an ecologist permaculture trainee.
-Adam
Adam K. Green, PhD
Program Coordinator Environmental Studies
Director Center for Sustainability
Santa Barbara City College
721 Cliff Dr.
Biological Sciences, EBS 323
Santa Barbara, CA 93109-2394
office: (805) 965-0581 ext 2394
fax: (805) 730-3050
email: green at sbcc.edu
http://sustainability.sbcc.edu
>>> Diana Liu <diana1127 at sbcglobal.net> 4/11/2008 8:08 am >>>
Hi, Cory. I agree with you. It's definitely not a black and white thing. There is so much that we don't know about nature. Someone mentioned (I think Larry) once that it's just how plants propagate, spreading their seeds (and genes) anywhere they go. So, are there really so called "native" vs. "non-native" (and therefore invasive plants)? Again, these are labels that we, human invented.
I would think that there could be a lot of cross pollination and hybridization between the "native" and "invasive" plants. As a consequence, may create progenies (diversity) that are more adaptive than either parent plants. Isn't diversity the golden rule for sustainability to happen?
Cory Brennan <cory8570 at yahoo.com> wrote:
I think the problem is more of a situation where permaculture principles are not applied, by either side. I know of a number of situations with invasive species that were quite destructive and disruptive of ecosystems, destroying forests, waterways, etc. It is usually not a black or white situation. You have to go in and actually observe the ecosystem in question and find out what is happening and why. Sometimes that isn't obvious. For instance, beetle invasions that kill forests may not have happened if the forests had not been weakened in a number of ways first by man's intervention (clear cut, replanting of single species, incorrect fire management techniques, pollution, etc, etc). Application of microbes can stop invasions as the system is strengthened - I personally don't know of any situation where artificial chemical solutions would be "necessary". In other cases, like mustard, there are adaptability features that native species don't have.
The review of this book makes it sound as extreme as those it is criticizing - I tend to distrust anything that makes things so black and white, from any side. My view is that you have to observe and then do what will be least disruptive to the existing system, as per permaculture principles. A great argument for natives is that we too often don't know their use and we really should bother to find out. So often, they offer more nutrition and other uses than imported species. California natives such as the oak are amazing plants and have so many great uses. Cutting them down to bring in cattle and strip mining has caused very easily observed damage to ecosystems, including massive erosion problems.
I think the argument of natives vs non native is a bit of a red herring. The real issue is whether we are observing the effects we create on our ecosystems and the implications of those effects, and taking responsiblity for that or not.
By the way, someone mentioned on one of these lists plants that are compatible with live oak. Is there a list? I'm familiar with some, but not all.
Cory
Marc Bailey <playtoe1 at yahoo.com> wrote: var YAHOO = {'Shortcuts' : {}}; YAHOO.Shortcuts.hasSensitiveText = true; YAHOO.Shortcuts.sensitivityType = ["sensitive_news_terms", "adult"]; YAHOO.Shortcuts.doUlt = false; YAHOO.Shortcuts.location = "us"; YAHOO.Shortcuts.document_id = 0; YAHOO.Shortcuts.document_type = ""; YAHOO.Shortcuts.document_title = "Interesting perspective about invasive species"; YAHOO.Shortcuts.document_publish_date = ""; YAHOO.Shortcuts.document_author = "playtoe1 at yahoo.com"; YAHOO.Shortcuts.document_url = ""; YAHOO.Shortcuts.document_tags = ""; YAHOO.Shortcuts.annotationSet = { "lw_1207900164_0": { "text": "http://jlhudsonseeds.net/Books.htm#Invasion%20Biology", "extended": 0, "startchar": 1140, "endchar": 1192, "start": 1140, "end": 1192, "extendedFrom": "", "predictedCategory": "", "predictionProbability": "0", "weight": 1, "type": ["shortcuts:/us/instance/identifier/hyperlink/http"], "category": ["IDENTIFIER"], "context": "other\x27s on this
list would find interesting. Happy composting, -Marc http://jlhudsonseeds.net/Books.htm#Invasion%20Biology We have all heard the breathless tales of the dangers", "metaData": { "linkHref": "http://jlhudsonseeds.net/Books.htm#Invasion%20Biology", "linkProtocol": "http", "linkRel": "nofollow", "linkTarget": "_blank" } }, "lw_1207900164_1": { "text": "Florida", "extended": 0, "startchar": 1779, "endchar": 1785, "start": 1779, "end": 1785, "extendedFrom": "", "predictedCategory": "PLACE", "predictionProbability": "0.959674", "weight": 0.35, "type": ["shortcuts:/us/instance/place/destination", "shortcuts:/us/instance/place/us/state"], "category": ["PLACE"], "context": "invasive alien\x22 hydrilla supports the highest bird species diversity in Florida, and it supports higher fish species density and many times", "metaData": { "geoArea": "148514", "geoCountry": "United States", "geoIsoCountryCode": "US", "geoLocation": "(-81.541183, 27.975639)", "geoName": "Florida",
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I've been thinking about plants labeled as invasive species and how many of them have extremely positive aspects. Much time, effort, and money is spent fighting these plants, but perhaps our energies could be directed in more fruitful ways (pun intended).
Coincidentally, a book that I had been reading called "Edible Forest Gardens" (Jacke & Toensmeier) recomends another book: "Invasion Biology: Critique of a Pseudoscience". I went to the website and found the following synopsys of the book that I thought other's on this list would find interesting.
Happy composting,
-Marc
http://jlhudsonseeds.net/Books.htm#Invasion%20Biology
We have all heard the breathless tales of the dangers of "invasive alien species," but what does science say about them? Did you know that studies show that purple loosestrife does not affect species richness of native plants? Or that it supports higher bird densities than native vegetation? That saltcedar supports native birds and insects in high numbers and at high levels of diversity, including endangered species? That the "invasive alien" hydrilla supports the highest bird species diversity in Florida, and it supports higher fish species density and many times the fish biomass than natives? That the zebra mussel increased the catch of yellow perch five-fold, and that it improves water quality? That the so-called "killer algae" reduces pollution and helps native species? That in all cases, including even oceanic islands, introduced species have increased biodiversity?
Thoroughly researched, with full citations to scientific literature, this book will definitely change your view of introduced species. It will give you the facts you need to counter those promoting invader fears.
Chapters cover the origins of "natural" ecosystems and their changes over time, and detail the true underlying causes of "invasion" in the damage industrialism is wreaking on the planet. Case studies of many of the most feared "invaders" are presented, each case showing the distortions of the nativists, and the beneficial effects of the newcomer. The resiliency of ecosystems and the rapid ecological integration of newcomers is demonstrated. A chapter details the growing extremism of the nativist movement, and the harm caused as they clearcut, bulldoze, herbicide, and burn natural areas around the world in the name of purifying the landscape of the "foreign," even killing endangered species as "invaders."
A detailed analysis of the writings of these nativists reveals the psychopathologies that drive this reactionary movement. Numerous quotes are compared which demonstrate that the same fears that underlie xenophobia, racism, and fascism fuel the anti-invader movement. A chapter covers in detail the pseudoscientific nature of invasion biology-why the invasive species model cannot be scientific, and the poor practices that characterize the field. The impossibility of predicting invasions is covered, showing the "white list" concept to be useless as public policy.
The hidden influence of the herbicide industry is exposed. The regulatory industry and corporate interests are colluding in an effort to leverage the fictitious "invasion crisis" into a system of complete bureaucratic control of nature, and corporate privatization of the earth's biological diversity.
The final chapters concern the beneficial, diversifying effects of anthropogenic dispersal-the movement of species by man. These species increase biological diversity, benefit ecosystems, prevent extinctions, and act as an important force for healing the planet. Dispersal is a powerful driving force of evolution, and the book concludes by pointing out a new direction for conservation-the incorporation of dispersal as an essential strategy.
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